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Abstract:

Rare earth oxy-nitride buffered III-N on silicon includes a silicon
substrate with a rare earth oxide (REO) structure, including several REO
layers, is deposited on the silicon substrate. A layer of single crystal
rare earth oxy-nitride is deposited on the REO structure. The REO
structure is stress engineered to approximately crystal lattice match the
layer of rare earth oxy-nitride so as to provide a predetermined amount
of stress in the layer of rare earth oxy-nitride. A III oxy-nitride
structure, including several layers of single crystal rare earth
oxy-nitride, is deposited on the layer of rare earth oxy-nitride. A layer
of single crystal III-N nitride is deposited on the III oxy-nitride
structure. The III oxy-nitride structure is chemically engineered to
approximately crystal lattice match the layer of III-N nitride and to
transfer the predetermined amount of stress in the layer of rare earth
oxy-nitride to the layer of III-N nitride.

Claims:

1. Rare earth oxy-nitride buffered III-N on silicon comprising: a
crystalline silicon substrate; a rare earth oxide structure deposited on
the silicon substrate and including a plurality of layers of single
crystal rare earth oxide; a layer of single crystal rare earth
oxy-nitride deposited on the rare earth oxide structure, the rare earth
oxide structure being stress engineered to approximately crystal lattice
match the layer of rare earth oxy-nitride so as to provide a
predetermined amount of stress in the layer of rare earth oxy-nitride; a
III oxy-nitride structure deposited on the layer of rare earth
oxy-nitride and including a plurality of layers of single crystal rare
earth oxy-nitride; and a layer of single crystal III-N nitride deposited
on the III oxy-nitride structure, the III oxy-nitride structure being
chemically engineered to approximately crystal lattice match the layer of
III-N nitride and to transfer the predetermined amount of stress in the
layer of rare earth oxy-nitride to the layer of III-N nitride, whereby
deformations in the layer of III-N nitride are substantially eliminated.

2. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 1
wherein the rare earth in the rare earth oxide structure and in the rare
earth oxy-nitride layer includes at least one of the lanthanides,
scandium and yttrium.

3. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 1
wherein the stress engineering in the rare earth oxide structure includes
gradually adjusting from the crystal lattice of the substrate to
approximately the crystal lattice of rare earth oxy-nitride layer.

4. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 3
wherein the gradual adjustment includes one of changing the rare earth in
each consecutive layer or using a gradually changing mix or alloy of
different rare earths to change the lattice spacing a desired amount.

5. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 4
wherein the rare earth included in the layer of rare earth oxy-nitride is
similar to the rare earth in an adjacent layer of the plurality of layers
of single crystal rare earth oxy-nitride.

6. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 1
wherein the III material in the III oxy-nitride structure includes a
material or combination of the materials in the group III metals of the
periodic table.

7. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 1
wherein the oxy-nitride in each of the plurality of layers of III
oxy-nitride is defined by the formula OxN.sub.(1-x) where
0.ltoreq.x≦1.

8. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim 7
wherein the chemical engineering includes altering x to alter the crystal
lattice of each layer of the plurality of layers of single crystal rare
earth oxy-nitride.

10. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim
9 wherein the rare earth oxide structure, the rare earth oxy-nitride
layer, the III oxy-nitride structure, and the III-N nitride layer are all
grown by one of MBE, MOCVD, PLD (pulsed laser deposition), sputtering,
and ALD (atomic layer deposition) in a one substrate single epitaxial
process.

11. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim
1 wherein the rare earth oxide structure includes at least two layers
each including two mixed rare earths, an amount of each of the two mixed
rare earths in each layer of the two layers being adjustable so as to
provide a predetermined amount of stress in the layer of rare earth
oxy-nitride.

12. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim
1 wherein the rare earth oxide structure includes a first layer defined
by the formula (M1.sub.xM2.sub.(l-x))2O3 where
0.ltoreq.x≦1 and a second layer defined by the formula
(M3.sub.yM4.sub.(1-y))2O3 where 0.ltoreq.y≦1 and M1, M2,
M3, and M4 are rare earth metals.

13. Rare earth oxy-nitride buffered III-N on silicon as claimed in claim
1 wherein the III-N nitride layer includes a first sub-layer defined by
the formula (III2.sub.xIII3.sub.(1-x))N where 0.ltoreq.x≦1 and a
second sub-layer defined by the formula (III4.sub.yIII5.sub.(1-y))N where
0.ltoreq.y≦1, and III2, III3, III4, and III5 are metals selected
from the group III metals in the periodic table.

14. Rare earth oxy-nitride buffered III-N on silicon comprising: a
crystalline silicon substrate; a rare earth oxide structure including a
first layer of rare earth metal oxide defined by the formula
(M1.sub.xM2.sub.(1-x))2O3 where 0.ltoreq.x≦1 deposited
on the substrate and a second layer of rare earth metal oxide defined by
the formula (M3.sub.yM4.sub.(1-y))2O3 where 0.ltoreq.y≦1
deposited on the first layer of rare earth metal oxide, and M1, M2, M3,
and M4 are rare earth metals; a layer of single crystal rare earth
oxy-nitride deposited on the rare earth oxide structure, the rare earth
oxide structure being stress engineered by varying x and y to
approximately crystal lattice match the layer of rare earth oxy-nitride
so as to provide a predetermined amount of stress in the layer of rare
earth oxy-nitride; a III oxy-nitride structure deposited on the layer of
rare earth oxy-nitride; and a layer of single crystal III-N nitride
deposited on the III oxy-nitride structure, the layer of single crystal
III-N nitride including a first sub-layer defined by the formula
(III2.sub.xIII3.sub.(1-x))N where 0.ltoreq.x≦1 and a second
sub-layer defined by the formula (III4.sub.yIII5.sub.(1-y))N where
0.ltoreq.y≦1, and III2, III3, III4, and III5 are metals selected
from the group III metals in the periodic table; the layer of rare earth
oxy-nitride and the III oxy-nitride structure being chemically engineered
to approximately crystal lattice match the layer of III-N nitride and to
transfer the predetermined amount of stress in the layer of rare earth
oxy-nitride to the layer of III-N nitride, whereby deformations in the
layer of III-N nitride are substantially eliminated; and a ratio
III2/III3 of the first sub-layer and a ratio III4/III5 of the second
sub-layer being varied by varying x and y, respectively, one of linearly
or step wise.

15. A method of fabricating rare earth oxy-nitride buffered III-N on
silicon comprising the steps of: providing a crystalline silicon
substrate; depositing a rare earth oxide structure on the silicon
substrate, the step including depositing a plurality of layers of single
crystal rare earth oxide in a stack on the substrate; depositing a layer
of single crystal rare earth oxy-nitride on the rare earth oxide
structure, the step including stress engineering the rare earth oxide
structure to approximately crystal lattice match the layer of rare earth
oxy-nitride to the rare earth oxide structure so as to provide a
predetermined amount of stress in the layer of rare earth oxy-nitride;
depositing a III oxy-nitride structure on the layer of rare earth
oxy-nitride, the step including depositing a plurality of layers of
single crystal rare earth oxy-nitride; and depositing a layer of single
crystal III-N nitride on the III oxy-nitride structure and chemically
engineering the III oxy-nitride structure to approximately crystal
lattice match the layer of III-N nitride to the III oxy-nitride structure
and to transfer the predetermined amount of stress in the layer of rare
earth oxy-nitride to the layer of III-N nitride, whereby deformations in
the layer of III-N nitride are substantially eliminated.

16. The method of claim 15 wherein the stress engineering in the rare
earth oxide structure includes gradually adjusting from the crystal
lattice of the substrate to approximately the crystal lattice of rare
earth oxy-nitride layer.

17. The method of claim 16 wherein the step of gradually adjusting
includes one of changing the rare earth in each consecutive layer or
using a gradually changing mix or alloy of different rare earths to
change the lattice spacing a desired amount.

18. The method of claim 16 wherein the oxy-nitride in each of the
plurality of layers of III oxy-nitride is defined by the formula
OxN.sub.(1-x) where 0.ltoreq.x≦1 and the step of chemical
engineering includes altering x to alter the crystal lattice of each
layer of the plurality of layers of single crystal rare earth
oxy-nitride.

19. The method as claimed in claim 15 wherein the step of depositing the
rare earth oxide structure includes depositing a first layer defined by
the formula (M1.sub.xM2.sub.(1-x))2O3 where 0.ltoreq.x≦1
and depositing a second layer defined by the formula
(M3.sub.yM4.sub.(1-y))2O3 where 0.ltoreq.y≦1 and M1, M2,
M3, and M4 are rare earth metals.

20. The method as claimed in claim 19 wherein the step of stress
engineering the rare earth oxide structure includes gradually varying x
and y.

21. The method as claimed in claim 15 wherein the step of depositing the
layer of single crystal III-N nitride includes depositing a first
sub-layer defined by the formula (III2.sub.xIII3.sub.(1-x))N where
0.ltoreq.x≦1 and depositing a second sub-layer defined by the
formula (III4.sub.yIII5.sub.(1-y))N where 0.ltoreq.y≦1, and III2,
III3, III4, and III5 are metals selected from the group III metals in the
periodic table.

22. The method as claimed in claim 21 wherein the step of depositing the
layer of single crystal III-N nitride further includes varying the ratios
of III2/III3 and III4/III5 by varying x and y, respectively, either
linearly or step wise.

Description:

FIELD OF THE INVENTION

[0001] This invention relates in general to the deposition of III-N
nitrides on silicon wafers.

BACKGROUND OF THE INVENTION

[0002] It has been found that III-N nitrides are a desirable semiconductor
material in many electronic and photonic applications. As understood in
the art, the III-N nitride semiconductor material must be provided as a
crystalline or single crystal formation for the most efficient and useful
bases for the fabrication of various electronic and photonic devices
therein. Further, the single crystal III-N nitride semiconductor material
is most conveniently formed on single crystal silicon wafers because of
the extensive background and technology developed in the silicon
semiconductor industry. However, because of the difference in spacing in
the crystal lattice structure it is extremely difficult to grow III-N
nitrides on silicon wafers.

[0003] It would be highly advantageous, therefore, to remedy the foregoing
and other deficiencies inherent in the prior art.

[0004] Accordingly, it is an object of the present invention to provide
new and improved methods of growing III-N nitrides on silicon substrates.

[0005] It is another object of the present invention to provide new and
improved methods of providing large diameter, high yield epitaxial wafers
of III-N nitrides on silicon.

[0006] It is another object of the present invention to provide new and
improved large diameter, high yield epitaxial wafers of III-N nitrides on
silicon.

SUMMARY OF THE INVENTION

[0007] Briefly, to achieve the desired objects and aspects of the instant
invention in accordance with a preferred embodiment thereof, provided is
a rare earth oxy-nitride buffered III-N nitride on a silicon substrate.
The embodiment includes a silicon substrate with a rare earth oxide (REO)
structure, including several REO layers, deposited on the silicon
substrate. A layer of single crystal rare earth oxy-nitride is deposited
on the REO structure. The REO structure is stress engineered to
approximately crystal lattice match the layer of rare earth oxy-nitride
so as to provide a predetermined amount of stress in the layer of rare
earth oxy-nitride. A III oxy-nitride structure, including several layers
of single crystal rare earth oxy-nitride, is deposited on the layer of
rare earth oxy-nitride. A layer of single crystal III-N nitride is
deposited on the III oxy-nitride structure. The III oxy-nitride structure
is chemically engineered to approximately crystal lattice match the layer
of III-N nitride and to transfer the predetermined amount of stress in
the layer of rare earth oxy-nitride to the layer of III-N nitride,
whereby deformations in the layer of III-N nitride are substantially
eliminated.

[0008] The desired objects and aspects of the instant invention are
further realized in accordance with a specific embodiment of rare earth
oxy-nitride buffered III-N on a silicon substrate. The embodiment
includes a crystalline silicon substrate with a rare earth oxide (REO)
structure deposited thereon. The REO structure includes a first layer of
rare earth metal oxide defined by the formula
(M1xM2.sub.(1-x))2O3, where 0≦x≦1, deposited
on the substrate and a second layer of rare earth metal oxide defined by
the formula (M3yM4.sub.(1-y))2O3, where
0≦y≦1, deposited on the first layer of rare earth metal
oxide, and M1, M2, M3, and M4 are rare earth metals. A layer of single
crystal rare earth oxy-nitride is deposited on the rare earth oxide
structure, the rare earth oxide structure being stress engineered by
varying x and y to approximately crystal lattice match the layer of rare
earth oxy-nitride so as to provide a predetermined amount of stress in
the layer of rare earth oxy-nitride. a III oxy-nitride structure is
deposited on the layer of rare earth oxy-nitride. A layer of single
crystal III-N nitride is deposited on the III oxy-nitride structure. The
layer of single crystal III-N nitride includes a first sub-layer defined
by the formula (III2xIII3.sub.(1-x))N, where 0≦x≦1,
and a second sub-layer defined by the formula
(III4yIII5.sub.(1-y))N, where 0≦y≦1, and III2, III3,
III4, and III5 are metals selected from the group III metals in the
periodic table. The layer of rare earth oxy-nitride and the III
oxy-nitride structure are chemically engineered to approximately crystal
lattice match the layer of III-N nitride and to transfer the
predetermined amount of stress in the layer of rare earth oxy-nitride to
the layer of III-N nitride, whereby deformations in the layer of III-N
nitride are substantially eliminated. A ratio III2/III3 of the first
sub-layer and a ratio III4/III5 of the second sub-layer is varied by
varying x and y, respectively, one of linearly or step wise.

[0009] The desired objects and aspects of the instant invention are
further realized in accordance with a method of fabricating rare earth
oxy-nitride buffered III-N on a silicon substrate including the steps of
depositing a rare earth oxide structure on a silicon substrate, the step
including depositing a plurality of layers of single crystal rare earth
oxide in a stack on the substrate. The method further includes the step
of depositing a layer of single crystal rare earth oxy-nitride on the
rare earth oxide structure, the step including stress engineering the
rare earth oxide structure to approximately crystal lattice match the
layer of rare earth oxy-nitride to the rare earth oxide structure so as
to provide a predetermined amount of stress in the layer of rare earth
oxy-nitride. The method further includes the step depositing a III
oxy-nitride structure on the layer of rare earth oxy-nitride, the step
including depositing a plurality of layers of single crystal rare earth
oxy-nitride. The method further includes the step of depositing a layer
of single crystal III-N nitride on the III oxy-nitride structure and
chemically engineering the III oxy-nitride structure to approximately
crystal lattice match the layer of III-N nitride to the III oxy-nitride
structure and to transfer the predetermined amount of stress in the layer
of rare earth oxy-nitride to the layer of III-N nitride, whereby
deformations in the layer of III-N nitride are substantially eliminated.

BRIEF DESCRIPTION OF THE DRAWING

[0010] The foregoing and further and more specific objects and advantages
of the instant invention will become readily apparent to those skilled in
the art from the following detailed description of a preferred embodiment
thereof taken in conjunction with the drawings, in which:

[0011] FIG. 1 is a simplified layer diagram of a stress engineered
epitaxial wafer in accordance with the present invention;

[0012]FIG. 2 is a more specific layer diagram of a stress engineered
epitaxial wafer similar to the wafer described in FIG. 1; and

[0013] FIG. 3 illustrates the stress developed by several rare earth
oxides relative to silicon.

DETAILED DESCRIPTION OF THE DRAWINGS

[0014] Referring to FIG. 1, a simplified layer diagram is illustrated of a
high yield epitaxial wafer 10 including III-N nitride on silicon in
accordance with the present invention. Wafer 10 includes a single crystal
silicon substrate 12 which, it will be understood, is or may be a
standard well know single crystal silicon wafer or portion thereof
generally known and used in the semiconductor industry. Single crystal
silicon substrate 12, it will be understood, is not limited to any
specific crystal orientation but could include <111> silicon,
<110> silicon, <100> silicon or any other orientation or
variation known and used in the art.

[0015] A rare earth oxide structure 14 is grown directly on the surface of
substrate 12 using any of the well known growth methods, such as MBE,
MOCVD, PLD (pulsed laser deposition), sputtering, ALD (atomic layer
deposition), or any other known growth method for thin films. Further,
the growth method used will generally be used for all additional layers
and may conveniently be employed to grow the entire structure in a
continuous process sometimes referred to herein as performed within a one
wafer single epitaxial process. Rare earth oxide structure 14 may be
considered a plurality of single crystal or crystalline layers or a
single layer of single crystal or crystalline material with a plurality
of sub-layers, either of which will be referred to herein for convenience
of understanding as a "plurality of layers". Further, rare earth oxide
structure 14 may vary from the bottom to the top (as described in more
detail below) and/or within each layer either linearly or in a step by
step process. In any case, rare earth oxide structure 14 is positioned
between the surface of substrate 12 and the lower surface of a single
crystal layer of rare earth oxy-nitride 16. Throughout this disclosure
whenever rare earth materials are mentioned it will be understood that
"rare earth" materials are generally defined as any of the lanthanides as
well as scandium and yttrium.

[0016] Rare earth oxide structure 14 is specifically designed or
engineered to gradually adjust from the crystal lattice of substrate 12
to approximately the crystal lattice of rare earth oxy-nitride layer 16,
also designated Mn oxy-nitride. This gradual adjustment of the
crystal lattice between the interface with substrate 12 and the interface
with layer 16 is generally designed to closely or approximately match the
lattice spacing between adjacent layers or to provide a predetermined
amount of stress or mismatch in lattice spacing. For example, layer 16
can be unstressed or stressed, either compressive or tensile, depending
on the selection or engineering of the rare earth composition in
structure 14. That is, structure 14 is selected or engineered such that
it constrains the overgrown rare earth oxy-nitride layer 16 to a
predetermined stress state, either unstressed, or compressive, or
tensile. The gradual adjustment of the crystal lattice spacing performed
in the growth of structure 14 is defined herein as stress engineering.

[0017] In this specific example, structure 14 varies or changes from
M1 oxide to Mn oxide, with `n` representing 2, 3, etc.
Generally, M, the rare earth in each layer (step or gradation), may
change or may be a mix or alloy of different rare earths to change the
lattice spacing the desired amount. For example, Gd2O3 has a
lattice spacing of 10.81 Å compared to 2aSi with a lattice
spacing of 10.86 Å, or approximately two times the lattice spacing of
silicon. Er2O3 has a lattice spacing of 10.55 Å
(Gd1-xErx)2O3 has a lattice spacing between 10.55
Å and 10.81 Å, depending upon the ratio of Gd and Er in the
material, and (Gd1-xNdx)2O3 has a lattice spacing
between 11.08 Å (the lattice spacing of Nd) and 10.81 Å,
depending upon the ratio of Gd and Nd in the material. Further, as
illustrated in FIG. 3, the stress curves of several different rare earth
oxides depict tensile stress for rare earth oxides with lattice spacing
greater than 2aSi and compressive stress for rare earth oxides with
a lattice spacing less than 2aSi. Thus, it can be seen that through
stress engineering of structure 14 any desired amount of stress, tensile
or compressive, can be provided in the rare earth oxy-nitride layer 16
while still retaining a single crystal or crystalline material.

[0018] In a preferred embodiment, the rare earth used in the final layer
of structure 14 (i.e. Mn oxide) is the same rare earth used in layer
16 of Mn oxy-nitride to provide the desired lattice matching.
However, in some applications it may be desirable to use a rare earth in
layer 16 that more closely lattice matches the lattice and lattice
spacing of a III oxy-nitride structure 18 grown on layer 16. As described
above in relation to structure 14, structure 18 may be considered a
plurality of single crystal or crystalline layers or a single layer of
single crystal or crystalline material with a plurality of sub-layers,
either of which will be referred to herein for convenience of
understanding as a "plurality of layers". In this embodiment, structure
18 includes a plurality of layers changing from III1 oxy-nitride to
IIIn oxy-nitride. Further, III oxy-nitride structure 18 may vary
from the bottom to the top and/or within each layer (as described in more
detail below) either linearly or in a step by step process.

[0019] In III oxy-nitride structure 18, the III material is any of the
materials or combinations of the materials in the group III metals of the
periodic table, including aluminum (Al), gallium (Ga), etc. Further, an
oxy-nitride is defined as a mix of oxygen and nitrogen according to the
formulas OxN.sub.(1-x) where 0≦X≦1. Preferably, the
III material in structure 18 remains the same but x varies between zero
and 1 as the structure is grown from layer 16 to a final layer 20 of
single crystal or crystalline III nitride. It should be noted that layer
20 can be conveniently grown by a continuation of the same process that
produces structure 18 by simply allowing x to go to zero. However, the
III material can vary from the lower layer of structure 18 (i.e. the
III1 oxy-nitride) abutting layer 16 to the upper layer (i.e. the
IIIn oxy-nitride) abutting layer 20. In a preferred embodiment, the
III material in the final layer of structure 18 (i.e. the IIIn
oxy-nitride) is the same as the III material in III nitride layer 20.

[0020] One major purpose of the varying structure 18 is to provide an
interface or chemical engineering between M, oxy-nitride layer 16 and
layer 20 of III nitride. That is, through chemical engineering the
crystal lattice of Mn oxy-nitride layer 16 is gradually matched to
the crystal lattice of III nitride layer 20 while retaining the stress
specifically engineered into Mn oxy-nitride layer 16. The stress is
specifically engineered to prevent or overcome any bowing or other
deformities or cracking in III nitride layer 20. Thus, a layer of single
crystal III nitride 20 can be conveniently grown with a much larger
diameter and with virtually any desired thickness. Because of the larger
diameter wafers that can be grown, a much higher yield can be realized.

[0021] Turning now to FIG. 2, a more specific embodiment of a stress
engineered epitaxial wafer 100 in accordance with the present invention
is illustrated. Wafer 100 includes a single crystal silicon substrate 120
which, it will be understood, is or may be a standard well know single
crystal silicon wafer or portion thereof generally known and used in the
semiconductor industry. Single crystal silicon substrate 120, it will be
understood, is not limited to any specific crystal orientation but could
include <111> silicon, <110> silicon, <100> silicon or
any other orientation or variation known and used in the art.

[0022] A rare earth oxide structure 140 is grown directly on the surface
of substrate 120 using any of the well known growth methods, such as MBE,
MOCVD, PLD (pulsed laser deposition), sputtering, ALD (atomic layer
deposition, or any other known growth method for thin films. Further, the
growth method used will generally be used for all additional layers and
may conveniently be employed to grow the entire structure in a continuous
process sometimes referred to herein as performed within a one wafer
single epitaxial process. Rare earth oxide structure 140 may be
considered a plurality of single crystal or crystalline layers or a
single layer of single crystal or crystalline material with a plurality
of sub-layers, either of which will be referred to herein for convenience
of understanding as a "plurality of layers". In any case, rare earth
oxide structure 140 is positioned between the surface of substrate 120
and the lower surface of a single crystal layer of rare earth oxy-nitride
160. Throughout this disclosure whenever rare earth materials are
mentioned it will be understood that "rare earth" materials are generally
defined as any of the lanthanides as well as scandium and yttrium.

[0023] Rare earth oxide structure 140 is specifically designed or
engineered to gradually adjust from the crystal lattice of substrate 120
to the crystal lattice of rare earth oxy-nitride layer 160, also
designated M5 oxy-nitride. This gradual adjustment of the crystal
lattice between the interface with substrate 120 and the interface with
layer 160 may be designed to closely match the lattice spacing between
adjacent layers or to provide a predetermined amount of stress or
mismatch in the lattice spacing. For example, layer 160 can be unstressed
or stressed, either compressive or tensile, depending on the selection or
engineering of the rare earth composition in structure 140. That is
structure 140 is selected or engineered such that it constrains the
overgrown rare earth oxy-nitride layer 160 to a predetermined stress
state, either unstressed, or compressive, or tensile. The gradual
adjustment of the crystal lattice performed in the growth of structure
140 is defined herein as stress engineering.

[0024] In this specific example, structure 140 includes two layers 142 and
144 each of which contains a mix of rare earths that vary either linearly
or step wise from a lower interface to an upper interface. Layer 142 is
illustrated with a formula (M1xM2.sub.(l-x))2O3 and layer
144 is illustrated with a formula (M3yM4.sub.(1-y))2O3.
M1, M2, M3, and M4 are rare earth metals as defined above. Further,
within layer 142 M1 and M2 vary with x being defined as
0≦x≦1. Also, within layer 144 M3 and M4 vary with y being
defined as 0≦y≦1. Rare earth oxide layers 142 and 144 may
vary from the bottom to the top either linearly or in a step by step
process.

[0025] Generally, M, the rare earth in each layer (step or gradation), may
change or may be a mix or alloy of different rare earths to change the
lattice spacing the desired amount, depending upon the values of x and y.
For example, Gd2O3 has a lattice spacing of 10.81 Å
compared to 2aSi with a lattice spacing of 10.86 Å, or
approximately two times the lattice spacing of silicon. Er2O3
has a lattice spacing of 10.55 Å, (Gd1-xErx)2O3
has a lattice spacing between 10.55 Å and 10.81 Å, depending upon
the ratio of Gd and Er in the material, and
(Gd1-xNdx)2O3 has a lattice spacing between 11.08
Å (the lattice spacing of Nd) and 10.81 Å, depending upon the
ratio of Gd and Nd in the material. Further, as illustrated in FIG. 3,
the stress curves of several different rare earth oxides depict tensile
stress for rare earth oxides with lattice spacing greater than 2aSi
and compressive stress for rare earth oxides with a lattice spacing less
than 2aSi. Thus, it can be seen that through stress engineering of
structure 140 any desired amount of stress, tensile or compressive, can
be provided in the rare earth oxy-nitride layer 160 while still retaining
a single crystal or crystalline material.

[0026] In the embodiment illustrated in FIG. 2, a single layer 170 of III1
oxy-nitride is illustrated which in conjunction with layer 160 of M5
oxy-nitride are chemically engineered to lattice match with a III nitride
structure 200 while transferring any stress engineered into layer 160
into III nitride structure 200. It will be understood that III1
oxy-nitride layer 170 can include a plurality of layers or sub-layers
(similar to structure 18 described above) that gradually change the
chemical interface from the rare earth oxy-nitride to III nitride
structure 200.

[0027] In this specific embodiment III nitride structure 200 includes two
layers 202 and 204 which are designated with the formulas
(III2xIII3.sub.(1-x))N and (III4yIII5.sub.(1-y))N,
respectively. III2, III3, III4, and III5 are metals selected from the
group III metals in the periodic table. Further, within layer 202 III2
and III3 vary with x being defined as 0≦x≦1 and within
layer 204 III4 and III5 vary with y being defined as 0≦y≦1.
Also, the ratios of III2/III3 and III4/III5 in layers 202 and 204,
respectively, can vary either linearly or step wise.

[0028] Thus, new and improved structure and methods of growing III-N
nitrides on silicon substrates have been disclosed. The new and improved
methods provide large diameter, high yield epitaxial wafers of III-N
nitrides on silicon. The new and improved methods result in a stress and
chemical engineered epitaxial wafer having a III N nitride layer with a
larger diameter and, therefore, a higher yield of final product. The
stress is specifically engineered to prevent or overcome any bowing or
other deformities or cracking in III nitride layer 20. Also, the high
yield epitaxial wafers of III-N nitrides on silicon can be grown within a
one wafer single epitaxial process.

[0029] Various changes and modifications to the embodiments herein chosen
for purposes of illustration will readily occur to those skilled in the
art. To the extent that such modifications and variations do not depart
from the spirit of the invention, they are intended to be included within
the scope thereof which is assessed only by a fair interpretation of the
following claims.